Radiation curable compositions

ABSTRACT

The invention relates to a radiation curable composition comprising radiation curable components wherein at least one component of the radiation curable composition contains a functional group which, when attached to an acrylate group has a calculated Boltzmann average dipole moment of higher than 3.5 Debye. The invention further relates to radiation curable optical fiber coating compositions having a high dielectric constant.

FIELD OF THE INVENTION

The invention relates to radiation curable compositions comprising aradiation curable oligomer, a radiation curable diluent, and optionallya radical generating photoinitiator. Such radiation curable compositionsare well known in the art.

DESCRIPTION OF RELATED ART

Radiation curable compositions are commonly used as protective coatingsor as adhesives. Important characteristics of these compositions are therate of cure, and the physical characteristics of the cured compositionsuch as e.g. pendulum hardness. The cure rate for a certain compositioncan be increased by increasing the amount of photoinitiator. Thishowever has certain drawbacks. Generally, photoinitiators are expensiveand these compounds yield extractable residues in the cured coating.Hence, increasing the amount of photoinitiator often is undesirable.

U.S. Pat. No. 5,047,261 discloses the use of a mono(meth)acrylatereactive diluent having a cyclic 5-membered ring carbonate functionalitywhich shows high reactivity in radiation crosslinkable compositions. InU.S. Pat. No. 5,047,261 a single reactive diluent is disclosed, whichsurprisingly gives a much higher reactivity and photosensitivity, andthus a higher rate of polymerization than other known reactive diluents.

U.S. Pat. No. 5,360,836 discloses the use of a mono(meth)acrylatereactive diluent having an oxazolidone ring. This reactive diluent alsoenhances the reactivity, in particular the rate of polymerization of aradiation curable composition.

These applications disclose reactive diluents that have very differentand non-relating structures and that have been found accidentally. Thereis no teaching disclosed that will enable the skilled man to developother reactive components that will also enhance the reactivity ofphotocrosslinkable compositions.

OBJECT OF THE INVENTION

It is an object of the present invention to find radiation curablecompositions that have enhanced reactivity and photosensitivity.

It is also an object of the present invention to find radiation curablecompositions that have a controlled reactivity and photosensitivity.

SUMMARY OF THE INVENTION

One or more of the above objects are obtained by a radiation curablecomposition comprising radiation curable components whereby at least onecomponent of the radiation curable composition contains a functionalgroup which functional group when attached to an acrylate group, has acalculated Boltzmann average dipole moment of higher than 3.5 Debye,excluding the components 2,3-carbonyldioxypropyl2-(meth)acryloyloxyethyl carbonate, 3,4-carbonyldioxybutyl2-(meth)acryloyloxyethyl carbonate, 5,6-carbonyldioxyhexyl2-(meth)acryloyloxyethyl, the acrylate of beta-hydroxyethyloxazolidone,and 2-oxo-1,3-dioxolan-4-yl-methyl acrylate.

The expression “functional group when attached to an acrylate group”covers components wherein the functional group is directly connected tothe acrylate group as well as components wherein the functional group isconnected to the acrylate group through an alkyl chain.

The “component containing a functional group which functional group whenattached to an acrylate group is having a calculated Boltzmann averagedipole moment of higher than 3.5 Debye” is further referred to as “thecomponent containing a functional group having a high dipole moment” andsaid component can contain a radiation curable functional group or not.When said component contains a radiation curable functional group, saidgroup can be chosen from the group consisting of methacrylate, acrylate,vinylether, fumarate, maleate, itaconate, oxolane or epoxy group.

DETAILED DESCRIPTION OF THE INVENTION

The improvement found by the present inventors is applicable in manyradiation curable compositions, but is particularly suitable in fiberoptic technology, adhesives and coatings for optical readable disks,hard coatings and stereolithography, as these fields of technologyrequire high cure speed and/or high light sensitivity, and/or highhardness.

The inventors found a relationship between the polarity of a radiationcurable composition and the rate of cure or polymerization upon exposureof light. An increase in the polarity or dielectric constant of aradiation curable composition causes an increase of the rate ofpolymerization. The dielectric value of the radiation curablecomposition is preferably enhanced by adding compounds that have highdipole moments. By addition of such compounds compositions can be madethat have dielectric constants of greater than 6. The dielectricconstant has been measured as indicated under the test method section.

For primary coatings according to the present invention that are used inoptical fiber technology the dielectric constant is preferably greaterthan 6.25. coating compositions with these high dielectric values showvery fast curing characteristics which ensures excellent mechanicalproperties and fast coating speeds of the glass fibers which is animportant demand in this technology.

For secondary coatings according to the present invention that are usedin optical fiber technology the dielectric constant is preferablygreater than 7.0.

For matrix materials according to the present invention that are used inoptical fiber technology the dielectric constant is preferably greaterthan 8.75.

For clear compositions according to the present invention that are usedin optical fiber technology as a base composition for a colored coatingor an ink composition the dielectric constant is preferably greater than8.25.

The radiation curable compositions of the present invention preferablycontain oligomer (A) and/or diluent (B) of which (A), (B) or bothcontain one or more functional groups having high dipole moments.

Preferably the dipole moment of the functional group, when attached toan acrylate group, is greater than 4.0 Debye, more preferable greaterthan 4.5 Debye, even more preferably greater than 5.0 Debye,particularly preferred greater than 5.5 Debye, and most preferablygreater than 6.0 Debye.

Preferably, the component containing a functional group having a highdipole moment is present in the radiation curable composition of thepresent invention in an amount of at least about 3 wt. % relative to thetotal amount of components in the composition, more preferably at leastabout 5 wt. %, even more preferably at least about 10 wt. %,particularly preferred at least about 15 wt. %, and most preferred atleast about 20 wt. %. Said component is preferably present in an amountof about 98 wt. % or less relative to the total amount of components inthe composition, more preferably 90 wt. % or less, particularlypreferred 80 wt. % or less and most preferred 60 wt % or less.

Preferably, the component containing a functional group having a highdipole moment is present in an amount sufficient to increase the curespeed as measured by RT FTIR with at least 3% double bond conversion persecond, more preferably at least 5%/sec, even more preferably at least10%/sec, particularly preferably at least 20%/sec and most preferred atleast 50%/sec.

The higher the dipole moment of the high dipole component, the lower theamount necessary to achieve a coating composition that has the desireddielectric constant.

Preferably, the radiation curable composition of the present inventioncomprises a mixture of a monofunctional reactive diluent having acalculated Boltzmann average dipole moment of lower than 3.5 Debye witha monofunctional reactive diluent having a calculated Boltzmann averagedipole moment of higher than 3.5 Debye, more preferably in a ratio atleast 60/40, even more preferred at least 50/50, particularly preferredat least 40/60 and most preferred at least 30/80. A particularlypreferred composition comprises as monofunctional reactive diluents onlymonofunctional acrylates having a calculated Boltzmann average dipolemoment of higher than 3.5 Debye.

The radiation curable composition of the present invention preferablycomprises a radiation curable oligomer (A) and a diluent (B). Preferablythe diluent (B) is a reactive diluent (B).

Functional groups having high dipole moments can be made in general bydirecting and fixing the individual dipole moments of the atoms of thegroup in substantially the same direction. Fixation of the structure canbe done for example by applying sterically demanding groups assubstituents or by making ring structures. Preferably the functionalgroups have ring structures. Preferably, said ring structures contain atleast one atom that is not a carbon atom. More preferably, at least oneatom, even more preferably, at least two atoms of said ring structuresis selected from the group consisting of O, P, N, S, and the like.

Examples of functional groups that have high dipole moments and fallunder the scope of the present invention are components having afunctional group chosen from the group consisting of 5-membered ringphosphate, 6-membered ring phosphate, 5-membered ring phosphite,6-membered ring phosphite, 4-membered ring lacton, 5-membered ringlacton, 6-membered ring lacton, 5-membered ring carbonate, 6-memberedring carbonate, 5-membered ring sulphate, 6-membered ring sulphate, 5ring sulphoxide, 6-membered ring sulphoxide, 6-membered ring amide,5-membered ring urethane, 6-membered ring urethane, 7-membered ringurethane, 5-membered ring urea, 6-membered ring urea, and 7-memberedring urea. Especially preferred are components that have a urethanegroup in the molecule and a 5 -membered ring phosphate, 6-membered ringphospate, 5-membered ring phosphite, 6-membered ring phosphite 4 ringlacton, 5-membered ring lacton, 6-membered ring lacton, 5-membered ringcarbonate, 6-membered ring carbonate, 5-membered ring sulphate,6-membered ring sulphate, 5 ring sulphoxide, 6-membered ring sulphoxide,5-membered ring amide, 6-membered ring amide, 7 ring amide, 5-memberedring urethane, 6-membered ring urethane, 7-membered ring urethane,5-membered ring urea, 6-membered ring urea, 7-membered ring urea group.

Also very reactive and preferred components are components having both acarbonate functionality in the molecule and a functionality selectedfrom the list consisting of a 5 ring phosphate, 6-membered ringphosphate, 5-membered ring phosphite, 6-membered ring phosphite,4-membered ring lacton, 5-membered ring lacton, 6-membered ring lacton,5-membered ring carbonate, 6-membered ring carbonate, 5-membered ringsulphate or sulphite, 6-membered ring sulphate or sulphite, 5-memberedring sulphite, 6-membered ring sulphite, 5 ring sulphoxide, 6-memberedring sulphoxide, 5-membered ring amide, 5-membered ring imide,6-membered ring amide, 7 ring amide, 5-membered ring imide, 6-memberedring imide, 5-membered ring thioimide, 6-membered ring thioimide,5-membered ring urethane, 6-membered ring urethane, 7-membered ringurethane, 5-membered ring urea, 6-membered ring urea and 7-membered ringurea group.

Preferred examples of components that have a functional group that havea calculated Boltzmann average dipole moment of 3.5 Debye or greaterwhen attached to an acrylate group are the components selected from thegroup consisting of lactones (C1) according to the formula (1):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅,R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkylgroup can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P; X is an oxygenor sulfur atom; Y is an oxygen or sulfur atom or an NR₇-group;; n is0-4; m is 0-4 and n+m=1-4; preferably n+m=2 or 3 and X, Y are oxygen; orcyclic carbonates (C2) according to formula (2):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkylgroup can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an arylgrouphaving from 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is0-4 and n+m=1-4, but excluding the compound where n=1, m=0, R₂, R₃, R₄=Hand R₁═CH₂CHCO₂CH₂ or R₁═CH₂CCH₃CO₂CH₂; preferably n+m=1 or 2 andX=Y=Z=oxygen; orcompounds (C3) according to the formula (3):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkylgroup can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an arylgrouphaving from 6-20 C-atoms; X and W are independently an oxygen or sulfuratom; Y is an oxygen or sulfur atom or an NR₇-group;; n is 0-4; m is 0-4and n+m=1-4; preferably n+m=1 or 2 and X=W=oxygen; ora compound (C4) according to the formula (4):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂, and R₃, are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkylgroup can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an arylgroup havingfrom 6-20 C-atoms; X and W are independently an oxygen or sulfur atom; nis 1-4; preferably n=2 or 3 and X=W=oxygen; ora compound (C5) according to the formula (5):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂, and R₃ are independently of each other H, an alkyl group having 1-20C atoms, wherein the alkylgroup can be linear, branched or cyclic andmay contain heteroatoms like ═N, O, S and P or an arylgroup having from6-20 C-atoms; X is an oxygen or sulfur atom; Y is an oxygen or sulfuratom or an NR₇-group; n is 1-5; p=0, 1; but excluding a compound whereinR₁═CH₂CHCO₂CH₂CH₂ or R₁═CH₂CCH₃CO₂CH₂CH₂ with n=2, 3 and X=Y=oxygen;preferably n=2 or 3. If p=0, than X is preferably oxygen, of p=1 than Xand Y are preferably oxygen;or a compound (C6) according to the formula (6):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkylgroup can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an arylgrouphaving from 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is0-4 and n+m=1-4; preferably n+m=1 or 2 and X, Y and Z are oxygen; ora compound (C7) according to the formula (7):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkylgroup can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an arylgrouphaving from 6-20 C-atoms; W, X, Y and Z are independently an oxygen orsulfur atom or an NR₇-group with the proviso that W and X are not bothan NR₇-group at the same time; n is 0-4; m is 0-4 and n+m=1-4;preferably n+m=1 or 2 and W, X, Y and Z are oxygen; ora compound (C8) according to the formula (8):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃, and R₇ are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkylgroup can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an arylgroup havingfrom 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 1-4;Preferably n=2 or 3 and Y and Z are oxygen;or a compound (C9) according to the formula (9):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃, and R₇ are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkylgroup can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an arylgroup havingfrom 6-20 C-atoms; X is an oxygen or sulfur atom; Y is an oxygen orsulfur atom or an NR₇-group; n is 1-4.

Preferably n=2 or 3 and X, Y and Z are oxygen.

Preferably, component (C6) is not ethylene urea ethyl methacrylate.

Preferably, in each of the components (C1) to (C9), one of the R₁ to R₇groups contains a radiation curable functional group, more preferably,R₁ contains a radiation curable functional group, even more preferablyan acrylate or methacrylate group.

The radiation curable composition according to the present invention canalso contain a non-reactive diluent having a calculated Boltzmannaverage dipole moment of greater than 3.5 Debye, more preferably greaterthan 4.0 Debye, even more preferable greater than 4.5 Debye,particularly preferred greater than 5.0 Debye, and most preferablygreater than 5.5 Debye. The non-reactive diluent can be present in thecomposition in similar amounts as given above for the high dipolereactive diluent. An example of a high dipole non-reactive diluentaccording to the present invention is propylene carbonate (D=5).Preferably, the high dipole non-reactive diluent is used together with ahigh dipole reactive diluent.

Preferably the radiation curable composition contains a radiationcurable oligomer (A) or a diluent (B) that comprises a NH- or OH-group,more preferably contains a radiation curable oligomer (A) and a diluent(B) that both comprise a NH- or OH-group, even more preferable aNH-group. It is This N-H or O—H group is non-ionogen and is thus capableof forming hydrogen bonds or improving hydrogen bonding. Preferredexamples of suitable N—H groups are amide groups, thioamide, urethaneand thiourethane groups.

Amongst reactive diluents that have a comparable high dipole moment inaccordance with the present invention, reactive diluents having anability of formation of H-bonds are preferred, such as reactive diluentscontaining a NH- or OH-group, since they show an additional increase onthe rate of polymerization of the radiation curable composition.

Preferably the components that contain a functional group also have aradiation curable functional group selected from the group consisting ofmethacrylate, acrylate, vinylether, fumarate, maleate, itaconate,oxolane or epoxy group, more preferably an acrylate or methacrylategroup.

Examples of preferred reactive diluents that can be present in theradiation curable compositions are one or more compounds having theformula (10):

wherein R₁₁=H or Me, R₁₂=organic group having 1-20 C-atoms and R₁₃ is aheterocyclic group of which the corresponding alcohol has a Boltzmannaverage dipolemoment of >2.0 Debye, more preferably at least 2.5 Debye,even more preferred at least 3.0 Debye, and most preferred at least 3.5Debye.

An alternative preferred example of a radiation curable diluent that canbe present in the radiation curable composition is a compound accordingto the formula (11):

wherein R₂₁=H or Me, R₂₂=organic group having 1-20 C-atoms, R₂₃=organicgroup having 1-20 C atoms and R₂₄ is a heterocyclic group of which thecorresponding alcohol has a Boltzmann average dipolemoment of >2.0Debye, more preferably at least 2.5 Debye, even more preferred at least3.0 Debye, and most preferred at least 3.5 Debye.

A different preferred example of a radiation curable component is acomponent having the the formula (12):

wherein R₃₁=H or Me, R₃₂, R₃₃ and R₃₄=are independently an organic grouphaving 1-20 C atoms, E oligomer or polymer with a molecular weightbetween 100 and 100000, X and Y are independently oxygen, sulphur or aNR₇-group, and R₃₅ is a heterocyclic group of which the correspondingalcohol has a Boltzmann average dipolemoment of >2.0 Debye, morepreferably at least 2.5 Debye, even more preferred at least 3.0 Debye,and most preferred at least 3.5 Debye.

More preferably E in formula (12) is an oligomer with a molecular weightbetween500 and 50000, and most preferred between 1000 and 10000.

Preferably, the above preferred component containing a heterocyclicgroup of which the corresponding alcohol has a dipole moment of greaterthan 2.5 Debye is present in the radiation curable composition of thepresent invention in an amount of at least about 3 wt. % relative to thetotal amount of components in the composition, more preferably at leastabout 5 wt. %, even more preferably at least about 10 wt. %. Saidcomponent is preferably present in an amount of about 98 wt. % or lessrelative to the total amount of components in the composition, morepreferably 90 wt. % or less, particularly preferred 80 wt. % or less andmost preferred 60 wt% or less. Preferably, said component is present inan amount sufficient to increase the cure speed as measured by RT FTIRwith at least 3% double bond conversion per second, more preferably atleast 5%/sec, even more preferably at least 10%/sec, particularlypreferably at least 20%/sec and most preferred at least 50%/sec.

The radiation curable components according to the present invention canbe prepared by reactions that are known to the skilled man. Examples ofsuch reactions are a process performed by reacting

(i) an hydroxy-, thiol-, or NH-functional (meth)acrylate, preferably, anhydroxy-functional (meth)acrylate,

(ii) a di-or more functional isocyanate, and

(iii) an hydroxy-, thiol-, or NH-functional compound having a Boltzmannaverage dipolemoment of >2.5 Debye together.

An example of preparation of the radiation curable reactive diluents isthe reaction of

(i) an hydroxy functional (meth)acrylate,

(ii) a di-functional isocyanate, and

(iii) an hydroxy functional compound having a Boltzmann averagedipolemoment of >2.5 Debye together.

A different process is carried out by reacting

(i) one equivalent hydroxy functional (meth)acrylate,

(ii) two equivalents of a di-functional isocyanate,

(iii) one equivalent of a di-amine, dihydroxy or dithiol functionalcompound with an molecular weight of 1000 or less, and

(iv) one equivalent of an hydroxy functional compound having a Boltzmannaverage dipolemoment of >2.5 Debye together.

A further embodiment relates to a process for the preparation of theradiation curable oligomer of the present invention by reacting

(i) one equivalent hydroxy functional (meth)acrylate,

(ii) two equivalents of a di-functional isocyanate,

(iii) one equivalent of a di-amine, dihydroxy or dithiol functionalcompound with an molecular weight Mn of greater than 1000, and

(iv) one equivalent of an hydroxy functional compound having a Boltzmannaverage dipolemoment of >2.5 Debye together.

An alternative process for the preparation of the radiation curableoligomer of the present invention is by reacting

(i) an hydroxy functional (meth)acrylate,

(ii) a tri- or more functional isocyanate,

(iii) an hydroxy functional compound having a Boltzmann average dipolemoment of >2.5 Debye together, and

(iv) an hydroxy-, amine- or thiol-functional oligomer with an averagehydroxy or amine functionality >1.5.

The invention is also relating to the use of the novel components andcompositions for making coatings, adhesives, inks, for coating of glassfibers and for stereolithography.

Preferably the radiation curable primary coating composition accordingto the present invention that is used in optical fiber technologycomprises a radiation curable oligomer (A), a reactive diluent (B),optionally a photoinitiator (D), wherein the radiation curable primarycoating composition has a dielectric constant of greater than 6.25, morepreferably greater than 6.5, even more preferably greater than 7.0,particularly preferred greater than 7.5, and most preferably greaterthan 8.0. Coating compositions with these high dielectric values showvery fast curing characteristics which ensures excellent mechanicalproperties and fast coating speeds of the glass fibers which is animportant demand in this technology.

Preferably the radiation curable secondary coating compositioncomprising a radiation curable oligomer (A), a reactive diluent (B),optionally a photoinitiator (D) has a dielectric constant of greaterthan 7.0, more preferably greater than 7.25, even more preferablygreater than 7.5, particularly preferred greater than 8.0, and mostpreferably greater than 8.5.

Preferably the radiation curable matrix material comprising a radiationcurable oligomer (A), a reactive diluent (B), optionally aphotoinitiator (D) has a dielectric constant of greater than 8.75, morepreferably greater than 9.0, even more preferably greater than 9.25,most preferably greater than 9.5.

Preferably the clear composition for a colored coating or an inkcomposition comprising a radiation curable oligomer (A), a reactivediluent (B), optionally a photoinitiator (D) has a dielectric constantof greater than 8.25, more preferably greater than 8.5, even morepreferably greater than 8.75, particularly preferred greater than 9.0,and most preferably greater than 9.5.

One way of achieving the fiber optic coating, matrix and ink compositionhaving the dielectric constant according to the present invention is bytaking a common fiber optic composition and by replacing therein amonofunctional reactive diluent having a low dipole moment by amonofunctional reactive diluent having a high dipole moment, preferablyby a monoacrylate component having a functional group which functionalgroup when attached to the acrylate group is having a dipole moment ofhigher than 3.5 Debye.

An alternative way of achieving the fiber optic coating, matrix and inkcomposition having the dielectric constant according to the presentinvention is by replacing a monofunctional reactive diluent having a lowdipole moment by a monoacrylate functional reactive diluent containing aNH-group and containing a functional group of which the correspondingalcohol is having a calculated Boltzmann average dipole moment ofgreater than 2.5 Debye.

Preferably, at least 3% of the monofunctional component is replaced withthe high dipole component, more preferably at least 5%, even morepreferably, at least 10%, particularly preferred at least 20%, and mostpreferred at least 30%. It is particularly preferred to completelyreplace the monofunctional component with the high dipole component ofthe present invention. The amount of high dipole component is chosensuch as to obtain a radiation curable composition having an optimalbalance between high cure speed and other properties, such as themechanical properties of the coating.

An alternative option is by replacing part of a urethane (meth)acrylateoligomer present in a common fiber optic composition with a urethane(meth)acrylate oligomer containing a heterocyclic group of which thecorresponding alcohol has a calculated Boltzmann average dipole momentof greater than 2.5 Debye. A further option is to formulate the fiberoptic coating, matrix or ink composition according to the presentinvention by using at least one of the components selected from the listconsisting of a high dipole moment non-reactive diluent (preferablyhaving a dipole moment of at least 3.5 Debye), a high dipole momentreactive diluent (preferably having a dipole moment of at least 3.5Debye), a high dipole moment oligomer, or mixtures thereof.

The reactivity and photosensitivity of the primary and secondary opticalfiber coatings of the present invention can also be improved by tuningthe volumetric thermal expansion coefficient at 23° C. (α₂₃) of thecoating.

The volumetric thermal expansion coefficient α₂₃ of a coating at 23° C.can be defined by the following formula (13):α₂₃=1/V(δV/δT)  (13)wherein V represents the specific volume (m³/kg) or the inverse of thedensity of the system, (δV/δT) represents the change in specific volumeof the system as a function of the temperature and T=23° C. The thermalexpansion coefficient δ₂₃ of several coating systems can be predicted onthe basis of chemical structural information by using a commercialsoftware package, module Synthia of MSI, as indicated in the test methodsection. In the present invention, δ₂₃ has been calculated in this way.

The present inventors have now found that the thermal expansioncoefficient δ₂₃ for the primary and secondary coatings of the presentinvention is related to the cohesive energy density, defined as thetotal amount of non-covalent interactions in the system, such ashydrogen bonding or dipolar interactions. Alternatively, one could saythat the volumetric expansion coefficient is related to the polarity ofthe system.

Therefore, according to one particular embodiment of the presentinvention, the expansion coefficient δ₂₃ of the primary and secondarycoating system can be decreased by increasing the cohesive energydensity (CED) or the polarity of the system, preferably by addingcomponents to the composition that have a functional group having adipole moment of greater than 2.5 Debye, more preferably, greater than3.5 Debye, particularly preferred by adding the high dipole componentsaccording to the present invention in the preferred amounts.

Therefore, an alternative aspect of the present invention relates to aradiation curable primary and secondary coating composition comprising aradiation curable oligomer (A), a reactive diluent (B), and optionally aphotoinitiator (D) having a calculated volumetric thermal expansioncoefficient α₂₃ of about 6.85×10⁻⁴ K⁻¹ or less. Said primary andsecondary coating compositions show an enhanced reactivity andphotosensitivity, and consequently a higher cure speed.

Preferably, the primary coatings have a volumetric thermal expansioncoefficient α₂₃ of about 6.70×10⁻⁴ K⁻¹ or less, more preferred about6.60×10⁻⁴ K⁻¹ or less, even more preferred about 6.50×10⁻⁴ K⁻¹ or less,and most preferred about 6.30×10⁻⁴ K⁻¹ or less.

Preferably, the α₂₃ of the secondary coating is about 6.5×10⁻⁴ K⁻¹ orless, particularly preferred, about 6.2×10⁻⁴ K⁻¹ or less, more preferredabout 6.0×10⁻⁴ K⁻¹ or less, and most preferred about 5.8×10⁻⁴ K⁻¹ orless.

The relation between α₂₃ and rate (cure speed) is shown for thefollowing secondary-type coatings U, V, W and Z as shown in Table 1. Thepolarity decreases going from composition U to Z. Said coatings havebeen prepared with an identical concentration of double bonds, and withthe same amount of di- or higher functional material, thus having thesame crosslink density. The rate has been measured by RT FTIR asdescribed in the test method section. TABLE 1 relation between α₂₃ andrate of secondary-type coatings U-Z Coating composition U V W ZComponents Wt. % Wt. % Wt. % Wt. % HEA-IPDI-pTHF1000-IPDI-HEA 50 50 5050 HEA 32.8 32.8 HEA-IPDI-5CC 17.2 SR504 17.2 5.5 Butyl acrylate 31Lauryl acrylate 19 Ethoxy ethyl acrylate 44.5 Irgacure 184 1 1 1 1Calculated α₂₃ (× 10⁻⁴ K⁻¹) 6.42 6.71 7.04 7.35 Rate (mol/l sec) 2.992.67 2.50 2.29Abbreviations and tradenames: HEA = 2-hydroxyethylacrylate; IPDI =isophorone diisocyanate; pTHF = polytetrahydrofuran having Mn of 1000;HEA-IPDI-5CC = component of Ex. 11; SR504 = ethoxylated (n = 4) nonylphenol acrylate; Irgacure 184 = photoinitiatorThe results in Table 1 show that the cure speed increases upondecreasing volumetric expansion coefficient (and thus increasingpolarity) of the coating system.

Suitable coating compositions for achieving the desired volumetricthermal expansion coefficient preferably contain one or more of thefollowing constituents: one or more reactive diluents selected from thegroup consisting of 1-(2-hydroxypropyl)3-phenoxy acrylate, vinylcaprolactam, vinyl pyrrolidone, N butylurethane O ethyl acrylate(CL1039), butyrolactone acrylate, acryloyloxy-dimethyl-butyrolactone, acomponent having a functional group which, when attached to an acrylategroup, has a calculated Boltzmann average dipole moment of greater than3.5, a component containing a heterocyclic group of which thecorresponding alcohol has a calculated Boltzmann average dipole momentof greater than 2.5 Debye, and the like, or mixtures thereof; one ormore oligomers selected from the group consisting of polyether(urethane) (meth)acrylate, polyester (urethane) (meth)acrylate,polyether/polycarbonate copolymer based (urethane) (meth)acrylate,polyether/polyester copolymer based (urethane) (meth)acrylate and thelike, of which, an ethylene oxide/butylene oxide based urethane(meth)acrylate and a polyether/polycarbonate copolymer based urethane(meth)acrylate are preferred.

The radiation curable composition of the present invention preferably issubstantially solvent free. This means that the composition as storedand/or applied does contain less than 5 wt %, preferably less than 2 wt% organic solvent that is not coreactive in polymerisation reactions.These solvents have to or will evaporate before, during or after cure.In a particular preferred embodiment, the amount of non reactive solventis less than 0.5 wt %.

The radiation curable composition preferably has more than 90 wt %radical curable components.

In another preferred embodiment, the composition is a hybrid which meansthat the composition further comprises a cationic curable component anda photo sensitive cationic initiator.

The radiation curable composition consists of a radiation curableoligomer and a radiation curable diluent. Each of the components may bemono or polyfunctional, poly meaning 2 or more functional. Generally,the functionality of the radiation curable components is 12 or lower.Preferred functionality for at least one of the components is 2-4.

The terms diluent and oligomer are used in this specification to denotea compound with lower or higher viscosity and/or molecular weightrespectively. The oligomer generally will have a molecular weight Mn ofabout 400 or higher, preferably between 500 and 100,000, more preferablybetween 1000 and 50,000, particularly preferred between 1500 and 20,000,and most preferably between 2000 and 10,000. The oligomer generally willhave an average functionality of about 1.2 or higher, preferably anaverage functionality of about 1.8-4.

The reactive diluent has a viscosity that is lower than the viscosity ofthe oligomer. In case an oligomer is used with high viscosity, thediluent may have a molecular weight up to about 700, preferably, up toabout 600, more preferably, up to about 500.

The present invention can be used in fiber optic coating materials,coating meaning primary or secondary coating, inks, ribbon matrixmaterials, encapsulating matrix materials, bundling materials and thelike.

Optical fiber coating materials may comprise as an oligomer a urethane(meth)acrylate oligomer, comprising an (meth)acrylate group, urethanegroups and a backbone. The backbone is derived from a polyol that hasbeen reacted with a diisocyanate and hydroxyalkylacrylate.

Examples of suitable polyols are polyether polyols, polyester polyols,polycarbonate polyols, amide polyols, polycaprolactone polyols, acrylicpolyols, and other polyols. These polyols may be used eitherindividually or in combinations of two or more. There are no specificlimitations to the manner of polymerization of the structural units inthese polyols. Any of random polymerization, block polymerization, orgraft polymerization is acceptable.

Given as examples of the polyether polyols are polyethylene glycol,polypropylene glycol, polypropylene glycol-ethyleneglycol copolymer,polytetramethylene glycol, polyhexamethylene glycol, polyheptamethyleneglycol, polydecamethylene glycol, and polyether diols obtained byring-opening copolymerization of two or more ion-polymerizable cycliccompounds. Here, given as examples of the ion-polymerizable cycliccompounds are cyclic ethers such as ethylene oxide, isobutene oxide,tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran,dioxane, trioxane, tetraoxane, cyclohexene oxide, styrene oxide,epichlorohydrin, isoprene monoxide, vinyl oxetane, vinyltetrahydrofuran, vinyl cyclohexene oxide, phenyl glycidyl ether, butylglycidyl ether, and glycidyl benzoate. Specific examples of combinationsof two or more ion-polymerizable cyclic compounds include combinationsfor producing a binary copolymer such as tetrahydrofuran and2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran,and tetrahydrofuran and ethylene oxide; and combinations for producing aternary copolymer such as a combination of tetrahydrofuran,2-methyltetrahydrofuran, and ethylene oxide, a combination oftetrahydrofuran, butene-1-oxide, and ethylene oxide, and the like. Thering-opening copolymers of these ion-polymerizable cyclic compounds maybe either random copolymers or block copolymers.

Included in these polyether polyols are products commercially availableunder the trademarks, for example, PTMG1000, PTMG2000 (manufactured byMitsubishi Chemical Corp.), PEG#1000 (manufactured by Nippon Oil andFats Co., Ltd.), PTG650 (SN), PTG1000 (SN), PTG2000 (SN), PTG3000,PTGL1000, PTGL2000 (manufactured by Hodogaya Chemical Co., Ltd.),PEG400, PEG600, PEG1000, PEG1500, PEG2000, PEG4000, PEG6000(manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and Pluronics (byBASF).

Polyester diols obtained by reacting a polyhydric alcohol and apolybasic acid are given as examples of the polyester polyols. Asexamples of the polyhydric alcohol, ethylene glycol, polyethyleneglycol, tetramethylene glycol, polytetramethylene glycol,1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol,2-methyl-1,8-octanediol, and the like can be given. As examples of thepolybasic acid, phthalic acid, dimer acid, isophthalic acid,terephthalic acid, maleic acid, fumaric acid, adipic acid, sebasic acid,and the like can be given.

These polyester polyol compounds are commercially available under thetrademarks such as MPD/IPA500, MPD/IPA1000, MPD/IPA2000, MPD/TPA500,MPD/TPA1000, MPD/TPA2000, Kurapol A-1010, A-2010, PNA-2000, PNOA-1010,and PNOA-2010 (manufactured by Kuraray Co., Ltd.).

As examples of the polycarbonate polyols, polycarbonate ofpolytetrahydrofuran, poly(hexanediol carbonate), poly(nonanediolcarbonate), poly(3-methyl-1,5-pentamethylene carbonate), and the likecan be given.

As commercially available products of these polycarbonate polyols,DN-980, DN-981 (manufactured by Nippon Polyurethane Industry Co., Ltd.),Priplast 3196, 3190, 2033 (manufactured by Unichema), PNOC-2000,PNOC-1000 (manufactured by Kuraray Co., Ltd.), PLACCEL CD220, CD210,CD208, CD205 (manufactured by Daicel Chemical Industries, Ltd.),PC-THF-CD (manufactured by BASF), and the like can be given.

Polycaprolactone diols obtained by reacting ε-caprolactone and a diolcompound are given as examples of the polycaprolactone polyols having amelting point of 0° C. or higher. Here, given as examples of the diolcompound are ethylene glycol, polyethylene glycol, polypropylene glycol,polypropylene glycol, tetramethylene glycol, polytetramethylene glycol,1,2-polybutylene glycol, 1,6-hexanediol, neopentyl glycol,1,4-cyclohexanedimethanol, 1,4-butanediol, and the like.

Commercially available products of these polycaprolactone polyolsinclude PLACCEL 240, 230, 230ST, 220, 220ST, 220NP1, 212, 210, 220N,210N, L230AL, L220AL, L220PL, L220PM, L212AL (all manufactured by DaicelChemical Industries, Ltd.), Rauccarb 107 (by Enichem), and the like.

As examples of other polyols ethylene glycol, 1,4-butanediol,1,5-pentanediol, 1,6-hexanediol, polyoxyethylene bisphenol A ether,polyoxypropylene bisphenol A ether, polyoxyethylene bisphenol F ether,polyoxypropylene bisphenol F ether, and the like can be given.

As these other polyols, those having a alkylene oxide structure in themolecule, in particular polyether polyols, are preferred. Specifically,polyols containing polytetramethylene glycol and copolymer glycols ofbutyleneoxide and ethyleneoxide are particularly preferred.

The reduced number average molecular weight derived from the hydroxylnumber of these polyols is usually from 50 to 15,000, and preferablyfrom 1,000 to 8,000.

Given as examples of the polyisocyanate used for the oligomer are2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylenediisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate,m-phenylene diisocyanate, p-phenylene diisocyanate,3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethanediisocyanate, 3,3′-dimethylphenylene diisocyanate, 4,4′-biphenylenediisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate,methylenebis(4-cyclohexylisocyanate), 2,2,4-trimethylhexamethylenediisocyanate, bis(2-isocyanatethyl)fumarate, 6-isopropyl-1,3-phenyldiisocyanate, 4-diphenylpropane diisocyanate, hydrogenateddiphenylmethane diisocyanate, hydrogenated xylylene diisocyanate,tetramethyl xylylene diisocyanate, lysine isocyanate, and the like.These polyisocyanate compounds may be used either individually or incombinations of two or more.

Examples of the hydroxyl group-containing (meth)acrylate used in theoligomer, include, (meth)acrylates derived from (meth)acrylic acid andepoxy and (meth)acrylates comprising alkylene oxides, more inparticular, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropylacrylate and2-hydroxy-3-oxyphenyl(meth)acrylate. Acrylate functional groups arepreferred over methacrylates.

The ratio of polyol, polyisocyanate, and hydroxyl group-containing(meth)acrylate used for preparing the urethane (meth)acrylate isdetermined so that 1.1 to 3 equivalents of an isocyanate group includedin the polyisocyanate and 0.1 to 1.5 equivalents of a hydroxyl groupincluded in the hydroxyl group-containing (meth)acrylate are used forone equivalent of the hydroxyl group included in the glycol.

In the reaction of these three components, an urethanation catalyst suchas copper naphthenate, cobalt naphthenate, zinc naphthenate, di-n-butyltin dilaurate, triethylamine, andtriethylenediamine-2-methyltriethyleneamine, and the like is usuallyused in an amount from 0.01 to 1 wt % of the total amount of thereactant. The reaction is carried out at a temperature from 10 to 90°C., and preferably from 30 to 80° C.

The number average molecular weight of the urethane (meth)acrylate usedin the composition of the present invention is preferably in the rangefrom 1200 to 20,000, and more preferably from 2,200 to 10,000. If thenumber average molecular weight of the urethane (meth)acrylate is lessthan 1000, the resin composition tends to solidify; on the other hand,if the number average molecular weight is greater than 20,000, theviscosity of the composition becomes high, making handling of thecomposition difficult.

The urethane (meth)acrylate is used in an amount from 5 to 90 wt %, andpreferably from 20 to 80 wt %, of the total amount of the resincomposition. When the composition is used as a coating material foroptical fibers, the range from 20 to 80 wt % is particularly preferableto ensure excellent coatability, as well as superior flexibility andlong-term reliability of the cured coating. The primary coatingcompositions according to the present invention preferably contain from20 to 70 wt. % oligomer and 80 to 30 wt. % of the high dipole component,more preferably from 30 to 60 wt. % oligomer and from 70 to 40 wt. % ofthe high dipole component, particularly preferred from 40 to 50 wt. %oligomer and from 60 to 50 wt. % of the high dipole component. Thesecondary coating, matrix and clear compositions according to thepresent invention preferably contain from 10 to 50 wt. % oligomer and 90to 50 wt. % of the high dipole component, more preferably from 20 to 40wt. % oligomer and from 80 to 60 wt. % of the high dipole component,particularly preferred from 25 to 30 wt. % oligomer and from 75 to 70wt. % of the high dipole component.

Other oligomers that can be used include polyester (meth)acrylate, epoxy(meth)acrylate, polyamide (meth)acrylate, siloxane polymer having a(meth)acryloyloxy group, a reactive polymer obtained by reacting(meth)acrylic acid and a copolymer of glycidyl methacrylate and otherpolymerizable monomers, and the like. Particularly preferred arebisphenol A based (meth)acrylateoligomers such as alkoxylated bisphenolA diacrylate and diglycidyl bisphenol ether A diacrylate. Combinationsof different oligomers may also be used for an optimization ofproperties of the cured products.

Suitable reactive diluents are examplified herein below.

Polymerizable vinyl monomers such as polymerizable monofunctional vinylmonomers containing one polymerizable vinyl group in the molecule andpolymerizable polyfunctional vinyl monomers containing two or morepolymerizable vinyl groups in the molecule may be added to the liquidcurable resin composition of the present invention.

Given as specific examples of the polymerizable monofunctional vinylmonomers are vinyl monomers such as N-vinylpyrrolidone,N-vinylcaprolactam, vinylimidazole, and vinylpyridine; (meth)acrylatescontaining an alicyclic structure such as isobornyl (meth)acrylate,bornyl (meth)acrylate, tricyclodecanyl (meth)acrylate, dicyclopentanyl(meth)acrylate, dicyclopentenyl (meth)acrylate, and cyclohexyl(meth)acrylate; benzyl (meth)acrylate, 4-butylcyclohexyl (meth)acrylate,acryloylmorpholine, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl (meth)acrylate, methyl (meth)acrylate,ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate,butyl (meth)acrylate, amyl (meth)acrylate, isobutyl (meth)acrylate,t-butyl (meth)acrylate, pentyl (meth)acrylate, isoamyl (meth)acrylate,hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate,isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl(meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl(meth)acrylate, dodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl(meth)acrylate, isostearyl (meth)acrylate, tetrahydrofurfuryl(meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol(meth)acrylate, benzyl(meth)acrylate, phenoxyethyl(meth)acrylate,polyethylene glycol mono(meth)acrylate, polypropylene glycolmono(meth)acrylate, methoxyethylene glycol (meth)acrylate, ethoxyethyl(meth)acrylate, methoxypolyethylene glycol (meth)acrylate,methoxypropylene glycol (meth)acrylate, diacetone(meth)acrylamide,isobutoxymethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide,t-octyl(meth)acrylamide, dimethylaminoethyl (meth)acrylate,diethylaminoethyl (meth)acrylate, 7-amino-3,7-dimethyloctyl(meth)acrylate, N,N-diethyl(meth)acrylamide,N,N-dimethylaminopropyl(meth)acrylamide, hydroxy butyl vinyl ether,lauryl vinyl ether, cetyl vinyl ether, 2-ethylhexyl vinyl ether,(meth)acrylatemonomers shown by the following formulas (14) to (16),

wherein R⁴¹ is a hydrogen atom or a methyl group, R⁴² is an alkylenegroup having 2-6, and preferably 2-4 carbon atoms, R⁴³ is a hydrogenatom or an organic group containing 1-12 carbon atoms or an aromaticring, and r is an integer from 0 to 12, and preferably from 1 to 8,

wherein R⁴¹ is the same as defined above, R⁴⁴ is an alkylene grouphaving 2-8, and preferably 2-5 carbon atoms, and q is an integer from 1to 8, and preferably from 1 to 4,

wherein R⁴¹, R⁴⁴, and q are the same as defined above.

Preferably, the radiation curable compositions according to the presentinvention do not contain methyl methacrylate.

As examples of commercially available products of the polymerizablemonofunctional vinyl monomers, Aronix M102, M110, M111, M113, M117(manufactured by Toagosei Co., Ltd.), LA, IBXA, Viscoat #190, #192,#2000 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), LightAcrylate EC-A, PO-A, NP-4EA, NP-8EA, M-600A, HOA-MPL (manufactured byKyoeisha Chemical Co., Ltd.), KAYARAD TC110S, R_(629,) R₆₄₄(manufactured by Nippon Kayaku Co., Ltd.), and the like can be given.

Given as examples of the polymerizable polyfunctional vinyl monomers arethe following (meth)acrylatecompounds: trimethylolpropanetri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene glycoldi(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethyleneglycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, neopentyl glycol di(meth)acrylate,trimethylolpropanetrioxyethyl (meth)acrylate,tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate,tris(2-hydroxyethyl)isocyanurate di(meth)acrylate,bis(hydroxymethyl)tricyclodecane di(meth)acrylate, di(meth)acrylate of adiol which is an addion compound of ethylene oxide or propylene oxide tobisphenol A, di(meth)acrylate of a diol which is an addition compound ofethylene oxide or propylene oxide to hydrogenated bisphenol A,epoxy(meth)acrylate obtained by the addition of (meth)acrylate todiglycidyl ether of bisphenol A, di(meth)acrylate of polyoxyalkylenebisphenol A, and triethylene glycol divinyl ether.

Examples of commercially available products of the polymerizablepolyfunctional vinyl monomers include Yupimer UV SA1002, SA2007(manufactured by Mitsubishi Chemical Corp.), Viscoat #195, #230, #215,#260, #335HP, #295, #300, #700 (manufactured by Osaka Organic ChemicalIndustry Co., Ltd.), Light Acrylate 4EG-A, 9EG-A, NP-A, DCP-A, BP4EA,BP-4PA, PE-3A, PE4A, DPE-6A (manufactured by Kyoeisha Chemical Co.,Ltd.), KAYARAD R-604, DPCA-20,-30,-60,-120, HX-620, D-310, D-330(manufactured by Nippon Kayaku Co., Ltd.), Aronix M-208, M-210, M-215,M-220, M-240, M-305, M-309, M-315, M-325 (manufactured by Toagosei Co.,Ltd.), and the like.

These polymerizable vinyl monomers are preferably used in an amount from1 to 70 wt %, and more preferably from 15 to 60 wt %, of the totalamount of the resin composition. If the amount is less than 10 wt %, theviscosity of the composition may become so high that coatability isimpaired. The amount exceeding 70 wt % may result in not only anincreased cure shrinkage, but also insufficient toughness of the curedproducts.

The liquid curable resin composition of the present invention is curedby radiation, and a photo-polymerization initiator can be used. Inaddition, a photosensitizer or synergist can be added as required. Givenas examples of the photo-polymerization initiator are1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-2-phenylacetophenone,xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone,triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone,4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone,benzoin propyl ether, benzoin ethyl ether, benzyl methyl ketal,1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one,2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanethone,diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone,2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one,2,4,6-trimethylbenzoyldiphenylphosphine oxide,bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide,bis-(2,4,6-trimethylbenzoyl)phenylphosphine oxide and the like. Mixturesof these photo-polymerization initiators may also be used.

Examples of commercially available products of the photo-polymerizationinitiator include IRGACURE 184, 369, 651, 500, 907, CGI1700, 1750, 1850,819, CG24-61, Darocur 11 16, 1173 (manufactured by Ciba SpecialtyChemicals Co., Ltd.), Lucirin LR₈₇₂₈ (manufactured by BASF), Ubecryl P36(manufactured by UCB), and the like.

Given as examples of the photosensitizer or synergist are triethylamine,diethylamine, N-methyldiethanolamine, ethanolamine,4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, and the like.As commercially available products of the photosensitizer, for example,Ebecryl P102, 103, 104, and 105 (manufactured by UCB) are given. Use ofmixtures of synergists is also possible.

The amount of the polymerization initiator used here is preferably inthe range from 0.1 to 10 wt %, and more preferably from 0.5 to 7 wt %,of the total amount of the components for the resin composition.

Beside the above-described components, other curable oligomers orpolymers may be added to the liquid curable resin composition of thepresent invention to the extent that the characteristics of the liquidcurable resin composition are not adversely affected.

An amine compound can be added to the liquid curable resin compositionof the present invention to prevent generation of hydrogen gas, whichcauses transmission loss in the optical fibers. As examples of the aminewhich can be used here, diallylamine, diisopropylamine, diethylamine,diethylhexylamine, and the like can be given.

In addition to the above-described components, various additives such asantioxidants, UV absorbers, light stabilizers, silane coupling agents,coating surface improvers, heat polymerization inhibitors, levelingagents, surfactants, colorants, preservatives, plasticizers, lubricants,solvents, fillers, aging preventives, and wettability improvers can beused in the liquid curable resin composition of the present invention,as required. Examples of antioxidants include Irganox1010, 1035, 1076,1222 (manufactured by Ciba Specialty Chemicals Co., Ltd.), Antigene P,3C, FR, Sumilizer GA-80 (manufactured by Sumitomo Chemical IndustriesCo., Ltd.), and the like; examples of UV absorbers include Tinuvin P,234, 320, 326, 327, 328, 329, 213 (manufactured by Ciba SpecialtyChemicals Co., Ltd.), Seesorb 102, 103, 110, 501, 202, 712, 704(manufactured by Sypro Chemical Co., Ltd.), and the like; examples oflight stabilizers include Tinuvin 292, 144, 622LD (manufactured by CibaSpecialty Chemicals Co., Ltd.), Sanol LS770 (manufactured by Sankyo Co.,Ltd.), Sumisorb TM-061 (manufactured by Sumitomo Chemical IndustriesCo., Ltd.), and the like; examples of silane coupling agents includeaminopropyltriethoxysilane, mercaptopropyltrimethoxy-silane, andmethacryloxypropyltrimethoxysilane, and commercially available productssuch as SH6062, SH6030 (manufactured by Toray-Dow Corning Silicone Co.,Ltd.), and KBE903, KBE603, KBE403 (manufactured by Shin-Etsu ChemicalCo., Ltd.); examples of coating surface improvers include siliconeadditives such as dimethylsiloxane polyether and commercially availableproducts such as DC-57, DC-190 (manufactured by Dow-Corning), SH-28PA,SH-29PA, SH-30PA, SH-190 (manufactured by Toray-Dow Corning SiliconeCo., Ltd.), KF351, KF352, KF353, KF354 (manufactured by Shin-EtsuChemical Co., Ltd.), and L-700, L-7002, L-7500, FK-024-90 (manufacturedby Nippon Unicar Co., Ltd.).

The viscosity of the liquid curable resin composition of the presentinvention is usually in the range from 200 to 20,000 mPa.sec, andpreferably from 2,000 to 15,000 mPa.sec.

The radiation-curable compositions of the present invention may beformulated such that the composition after cure has a modulus as low as0.1 MPa and as high as 2,000 MPa or more. Those having a modulus in thelower range, for instance, from 0.1 to 10 MPa, preferably 0.1 to 5 MPa,and more preferably 0.5 to less than 3 MPa are typically suitable forprimary coatings for fiber optics. More in particular, primary coatingswith an equilibrium modulus of less than 1.5 MPa, preferably less than1.3 MPa and more preferably less than 1.0 MPa are most preferred. Incontrast, suitable compositions for secondary coatings, inks and matrixmaterials generally have a modulus of above 50 MPa, with secondarycoatings tending to have a modulus more particularly above 100 up to2,000 MPa and matrix materials tending to be more particularly betweenabout 50 MPa to about 200 MPa for soft matrix materials, and between 200to about 1500 MPa for hard matrix materials. The radiation-curablecomposition of the present invention may be formulated such that thecomposition after cure has a Tg between −70° C. and 130° C. The Tg ismeasured as the peak tan-delta in a DMA curve at 2.5% elongation.

Elongation and tensile strength of these materials can also be optimizeddepending on the design criteria for a particular use. For curedcoatings formed from radiation-curable compositions formulated for useas primary coatings on optical fibers, the elongation-at-break istypically greater than 80%, more preferably the elongation-at-break isat least 110%, more preferably at least 150% but not typically higherthan 400%. For coatings formulated for secondary coatings, inks andmatrix materials the elongation-at-break is typically between 10% and100%, and preferably higher than 30%.

The glass transition temperature (Tg), measured as the peak tan-deltadetermined by dynamic mechanical analysis (DMA), can be optimizeddepending on the particulars of the application. The glass transitiontemperature may be from 10° C. down to −70° C. or lower, more preferablylower than 0° C. for compositions formulated for use as primary coatingsand 10° C. to 120° C. or higher, more preferably above 30° C., forcompositions designed for use as secondary coatings, inks and matrixmaterials.

The compositions of the present invention will preferably have a curespeed of 1.0 J/cm² of less (at 95% of maximum attainable modulus). Foran secondary coating, ink or matrix material, cure speed is preferablyabout 0.5 J/cm² or less (at 95% of maximum attainable modulus), and morepreferably, about 0.3 J/cm² or less, and even more preferably, about 0.2J/cm² or less.

The cured products obtained by the polymerization of the resincomposition of the present invention are particularly suitable for useas a coating material for optical fibers, optical fiber ribbons, and thelike including primary coatings, secondary coatings, colored secondarycoatings, inks, matrix materials and bundling materials.

The present invention also relates to a coated optical fiber comprisinga glass optical fiber, a primary coating applied thereon, a secondarycoating applied on the primary coating and optionally an ink compositionapplied on the secondary coating, wherein at least one of the primarycoating, secondary coating or ink composition comprises

a a radiation curable oligomer (A)

b a diluent (B),

wherein at least one of (A) or (B) is a component having a functionalgroup which has a calculated Boltzmann average dipole moment of higherthan 2.5 Debye and to an optical fiber ribbon comprising a plurality ofsaid coated, and optionally colored optical fibers arranged in a planeand embedded in a matrix composition.

The compositions of the present invention can very well be used as DVDadhesives or lackers on CD/DVD disks.

For an adhesive coating, density at 25° C. is about 1.02 g/ml. Theadhesive composition preferably has a viscosity of about 100 to about30,000 mPas at 25° C. Elongation is preferably at least 2% or more. Theshrinkage upon cure should be ≦7%, with respect to the density of curedmaterial. Bond strength is preferably rated about 4 to about 5. Shearstrength is preferably about 10 lbs to about 50 lbs. Cured adhesivebonds are preferably stable under exposure to about 85° C. at about 85%relative humidity for at least 96 hrs.

The compounds forming the radiation curable adhesive compositions arecombined to form a, preferably, thixotropic mixture and coated on, forexample, one surface of each of two polycarbonate substrates forming theDVD, which surfaces are already coated with an aluminum, gold or otherlayer encoded with audio, video or other information and preferablyprotected by a UV curable lacquer. The adhesive is coated on thesubstrates by screen printing or other suitable method known in the art.The adhesive on the substrates is then cured with ultraviolet radiationpreferably at a dose of about 0.2-1.0 J/cm², for example about 0.4J/cm². Radiation-cure may be effected using a fusion lamp equipped witha “H” bulb or a “D” bulb from Fusion Curing Systems, Rockville, Md., orthe equivalent thereof, in an air atmosphere. The cured adhesive coatedsubstrates are superimposed on each other with the adhesive bonding thesubstrate layers together, thereby forming a single DVD having one orpreferably two layers of encoded audio or video information which may beread in a DVD player. Substrate layers which may be bonded by theinvention in various combinations comprise plastics, metallics andceramics. The adhesive compositions are preferably applied to the disclayers by screen printing.

The production of and useful characteristics for optical disc adhesivesare discussed in, for example, U.S. Pat. Nos. 4,861,637, 4,906,6755,360,652, 5,663,211, 5,227,213 and 5,213,947.

In one embodiment of the invention, the compositions can comprise atleast one radiation-curable (meth)acrylate oligomer, at least oneradiation-curable reactive diluent, at least one photoinitiator, asdescribed above for optical glass fiber coatings. In another embodiment,the composition further comprises at least one epoxy compound,optionally at least one diol and optional additives. The weight ratio ofthe cationic component to the radically curable component of thecomposition may be from about 99:1 to about 20:80, preferably from about80:20 to as low as about 40:60, and more preferably is from about 60:40to about 50:50. Additives will bring the total weight value to 100% ineach case.

The composition may be tailored to maximize the adhesiveness, reduce theviscosity, shorten cure speed, and the like of the cured material. Forexample, radical polymerizable monomers and optionally silane compounds,may be added at varying effective concentrations to achieve improvedviscosity and adhesion, respectively. By altering the ratios ofcomponents, other desirable properties may be promoted, such as highoptical transparency, hardness, chemical resistance, and abrasionresistance.

If a hybrid composition is used, the composition contains at least onecationic curable epoxy resin, preferably present in an amount from about10 wt. % to about 99 wt. %. Suitable epoxy resins include bisphenol-A,cycloaliphatic epoxides, bisphenol-F, and mixtures thereof. Preferredepoxy resins include mixed cycloaliphatic epoxides,bis-(3,4-epoxycyclohexyl) adipate, bisphenol-A epoxide and bisphenol-Fepoxide. Bisphenol-A epoxide is known to give good surface cure.Excellent through cure is achievable with bisphenol-F epoxide, and ismost preferred.

The composition preferably comprises a polyol, which can be a lowmolecular compound (with e.g. an Mw of less than 500) and 2-6 hydroxygroups, preferably 2-3 hydroxy groups. Alcohols and polyols can behaveas chain transfer agents and as co-curing agents with epoxides,improving cure speed of cationic formulations. Suitable polyols includeε-caprolactone triol crosslinking agents of viscosities at 55° C.ranging from 2250 cP to 2700 cP. Other examples of suitable polyolsinclude ethyleneglycol, diethyleneglycol, 1,2-propanediol,1,3-propanediol, 1,2-butanediol, 1,4-butanediol, pentaeritritol,trimethylolpropane and the like. The amount of the polyol—ifpresent—preferably is 1 to 70 wt %, preferably 2-50 wt % and mostpreferred 3-20 wt %. Low molecular polyols and in particular diolshaving 1-8 carbon atoms are preferred because these aid in achieving alow viscosity. Ethyleneglycol is most preferred.

Hybrid compositions often are used in stereolithography, or3D-modelling. The cationic curable component generally has a molecularweight of between 120 and 10,000, preferably between 150 and 5,000, morepreferably between 180 and 2,000.

Examples of such a compound include epoxy compounds, oxetane compounds,oxolane compounds, cyclic acetal compounds, cyclic lactone compounds,thiirane compounds, thiethane compounds, vinyl ether compounds, spiroorthoester compounds obtained by the reaction of an epoxy compound withat least one lactone compound, ethylenically unsaturated compound,cyclic ether compound, cyclic thioether compound, vinyl compound, and/orthe like.

Preferred cationically polymerizable organic compounds include glycidylether compounds, including di-, tri- and polyglycidyl ether compounds,and alicyclic ether compounds including those comprising residue ofcarboxylic acids such as, for example, alkylcarboxylic acid residualgroups, alkylcycloalkylcarboxylic acid residual groups and dialkyldicarboxylic acid residual groups. Suitable epoxy compounds that can beused include, for example, bisphenol A diglycidyl ether, bisphenol Fdiglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol Adiglycidyl ether, brominated bisphenol F diglycidyl ether, brominatedbisphenol S diglycidyl ether, epoxy novolak resin, hydrogenatedbisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether,hydrogenated bisphenol S diglycidyl ether,3,4-epoxycyclohexylmethyl-3′,4′-epoxycyclohexanecarboxylate,2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-1,4-dioxane,bis(3,4-epoxycyclohexylmethyl)adipate, vinylcyclohexene oxide,4-vinylepoxycyclohexane,bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate,3,4-epoxy-6-methylcyclohexyl-3′,4′-epoxy-6′-methylcyclohexanecarboxylate,methylenebis(3,4-epoxycyclohexane), dicyclopentadiene diepoxide,di(3,4-epoxycyclohexylmethyl) ether of ethylene glycol,ethylenebis(3,4-epoxycyclohexanecarboxylate),epoxyhexahydrodioctylphthalate, epoxyhexahydro-di-2-ethylhexylphthalate, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidylether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether,polyethylene glycol diglycidyl ether, polypropylene glycol diglycidylether, polyglycidyl ethers of polyether polyol obtained by the additionof one or more alkylene oxides to aliphatic polyhydric alcohols such asethylene glycol, propylene glycol, and glycerol, diglycidyl esters ofaliphatic long-chain dibasic acids, monoglycidyl ethers of aliphatichigher alcohols, monoglycidyl ethers of phenol, cresol, butyl phenol, orpolyether alcohols obtained by the addition of alkylene oxide to thesecompounds, glycidyl esters of higher fatty acids, epoxidated soybeanoil, epoxybutylstearic acid, epoxyoctylstearic acid, epoxidated linseedoil, epoxidated polybutadiene, and the like can be given.

Examples of other cationically polymerizable organic compounds which canbe used include oxetanes such as trimethylene oxide,3,3-dimethyloxetane, 3,3-dichloromethyloxetane,3-ethyl-3-phenoxymethyloxetane, and bis(3-ethyl-3-methyloxy)butane;oxolanes such as tetrahydrofuran and 2,3-dimethyltetrahydrofuran; cyclicacetals such as trioxane, 1,3-dioxolane, and 1,3,6-trioxanecyclooctane;cyclic lactones such as β-propylolactone and ε-caprolactone; thiiranessuch as ethylene sulfide, 1,2-propylene sulfide, andthioepichlorohydrin; thiethanes such as 3,3-dimethylthiethane; vinylethers such as ethylene glycol divinyl ether, triethylene glycol divinylether, trimethylolpropane trivinyl ether; spiro orthoesters obtained bythe reaction of an epoxy compound and lactone; ethylenically unsaturatedcompounds such as vinylcyclohexane, isobutylene, and polybutadiene;derivatives of the above compounds; and the like.

Of these cationically polymerizable organic compounds, bisphenol Adiglycidyl ether, bisphenol F diglycidyl ether, hydrogenated bisphenol Adiglycidyl ether, hydrogenated bisphenol F diglycidyl ether,3,4-epoxycyclohexylmethyl-3′,4′-epoxycyclohexanecarboxylate,bis(3,4-epoxycyclohexylmethyl)adipate, 1,4-butanediol diglycidyl ether,1,6-hexanediol diglycidyl ether, glycerol triglycidyl ether,trimethylolpropane triglycidyl ether, neopentyl glycol diglycidyl ether,polyethylene glycol diglycidyl ether, and polypropylene glycoldiglycidyl ether are preferable.

As even more preferred cationically polymerizable organic compoundsepoxy compounds having two or more alicyclic epoxy groups in a moleculesuch as 3,4-epoxycyclohexylmethyl-3′,4′-epoxycyclohexanecarboxylate, andbis(3,4-epoxycyclohexylmethyl)adipate can be given.

As examples of commercially available products of the cationicallypolymerizable organic compounds suitably used, UVR-6100, UVR-6105,UVR-6110, UVR-6128, UVR-6200, UVR-6216 (manufactured by Union CarbideCorp.), Celoxide 2021, Celoxide 2021P, Celoxide 2081, Celoxide 2083,Celoxide 2085, Celoxide 2000, Celoxide 3000, Glycidole, AOEX 24,Cyclomer A200, Cyclomer M100, Epolead GT-300, Epolead GT-301, EpoleadGT-302, Epolead GT-400, Epolead 401, Epolead 403 (manufactured by DaicelChemical Industries, Ltd.), Epicoat 828, Epicoat 812, Epicoat 1031,Epicoat 872, Epicoat CT508 (manufactured by Yuka-Shell Epoxy K.K.),KRM-2100, KRM-2110, KRM-2199, KRM-2400, KRM-2410, KRM-2408, KRM-2490,KRM-2200, KRM-2720, KRM-2750 (manufactured by Asahi Denka Kogyo Co.,Ltd.), Rapi-Cure DVE-3, CHVE, PEPC (manufactured by ISP), VECTOMER 2010,2020, 4010, 4020 (manufactured by AlliedSignal), and the like can begiven.

The proportion of the cationic curable component used in thephotocurable resin composition of the present invention is usually,relative to the total compositon, 20-85 wt %, preferably 30-80 wt %, andmore preferably 40-75 wt %. If the proportion is too small,three-dimensional objects formed from the resin composition may exhibitinsufficient dimensional accuracy and deformation with time may becaused. On the other hand, if the proportion is too large, the resincomposition may exhibit inferior photocurability which may result ininefficient fabrication.

Hybrid resin compositions as for example used in DVD adhesives or 3Dmodelling preferably comprise a cationic photoinitiator.

The cationic photopolymerization initiator of the photocurable resincomposition of the present invention evolves a material which initiatescationically polymerization by exposure to energy rays such asradiation. Here, energy rays such as radiation include visible rays,ultraviolet rays, infrared rays, X-ray, α-rays, β-rays, γ-rays, and thelike. As examples of preferable compounds used as the component (B),onium salts represented by formula (17) can be given:[R⁵¹ _(a)R⁵² _(b)R⁵³ _(c)R⁵⁴ _(d)W]^(+m) [MX_(n+m)]^(−m)  (17)wherein a cation is an onium ion; W represents S, Se, Te, P, As, Sb, Bi,O, I, Br, Cl, or —N≡N; R⁵¹, R⁵², R⁵³, and R₅₄ independently representorganic groups; a, b, c, and d independently represent integers from0-3, provided that the total of (a+b+c+d) is equal to the of valence ofW; M is a metal or a metalloid which constitutes a center atom of thehalide complex [MX_(n+m)]^(−m), for example, M represents B, P, As, Sb,Fe, Sn, Bi, Al, Ca, In, Ti, Zn, Sc, V, Cr, Mn, Co; X represents ahalogen atom such as F, Cl, and Br; m represents a positive charge of ahalide complex ion; and n represents a valence of M. This onium saltevolves Lewis acids by irradiation.

As specific examples of an anion [MX_(n+m)]^(−m) in the above formula(17), tetrafluoroborate (BF₄ ⁻), hexafluorophosphate (PF₆ ⁻),hexafluoroantimonate (SbF₆ ⁻), hexafluoroarsenate (AsF₆ ⁻),hexachloroantimonate (SbCl₆ ⁻), tetrakispentafluorophenylborate and thelike can be given.

Moreover, onium salts having an anion represented by the formula[MXn(OH)—] and onium salts having other anions such as perchloric acidion (ClO₄ ⁻), trifluoromethane sulfonic acid ion (CF₃SO₃ ⁻),fluorosulfonic acid ion (FSO₃ ⁻), toluenesulfonic acid ion,trinitrobenzenesulfonic acid anion, trinitrotoluenesulfonic acid anioncan also be used.

Of these onium salts, aromatic onium salts are more preferred. Examplesof such aromatic onium salts include: aromatic halonium salts disclosedin, for example, Japanese Patent Applications Laid-open No. 151996/1975and No. 158680/1975, VIA group aromatic onium salts disclosed in, forexample, Japanese Patent Applications Laid-open No. 151997/1975, No.30899/1977, No. 55420/1981, and No.125105/1980; VA group aromatic oniumsalts disclosed in, for example, Japanese Patent Application Laid-openNo. 158698/1975; oxosulfoxonium salts disclosed in, for example,Japanese Patent Applications Laid-open No. 8428/1981, No. 149402/1981,and No.192429/1982; aromatic diazonium salts disclosed in, for example,Japanese Patent Application Laid-open No. 17040/1974; thiopyrylium saltsdisclosed in, for example, U.S. Pat. No. 4,139,655; and the like. Inaddition, iron/allene complex initiators, aluminum complex/photolysissilicon compound initiators, and the like can also be given as examples.

As examples of commercially available products of cationicphotopolymerization initiators, UVI-6950, UVI-6970, UVI-6974, UVI-6990(manufactured by Union Carbide Corp.), Adekaoptomer SP-150, SP-151,SP-170, SP-171 (manufactured by Asahi Denka Kogyo Co., Ltd.), Irgacure261 (manufactured by Ciba Specialty Chemicals Co., Ltd.), CI-2481,CI-2624, CI-2639, CI-2064 (manufactured by Nippon Soda Co., Ltd.),CD-1010, CD-1011, CD-1012 (manufactured by Sartomer Co., Ltd.), DTS-102,DTS-103, NAT-103, NDS-103, TPS-103, MDS-103, MPI-103, BBI-103(manufactured by Midori Chemical Co., Ltd.), PCI-061T, PCI-062T,PCI-020T, PCI-022T (manufactured by Nippon Kayaku Co., Ltd.), and thelike can be given. Of these, UVI-6970, UVI-6974, Adekaoptomer SP-170,SP-171, CD-1012, and MPI-103 are particularly preferable in view ofhigher photocuring sensitivity of the resulting resin composition.

These cationic photopolymerization initiators can be used eitherindividually or in combinations of two or more.

The proportion of the cationic initiator used in the photocurable resincomposition of the present invention is usually, relative to the totalweight of the composition, 0.1-10 wt %, preferably 0.2-5 wt %, and morepreferably 0.3-3 wt %.

A further preferred compound in hybrid compositions is a polyol havingtwo or more hydroxyl groups, preferably three or more hydroxyl groups.

The polyol having two or more hydroxyl groups is a component fordeveloping the photo-curability of the resin composition. The polyolprovides assistance to the three-dimensional object to preventdeformation over time (i.e., shape stability) and resistance to changein mechanical characteristics over time (i.e., physical propertystability). Preferably, the polyol has two or more, preferably 2-6hydroxyl groups. If polyols having more than six hydroxyl groups areused, the elongation and toughness of the resulting three-dimensionalobject tends to be lower.

Preferred examples include polyether polyols having three or more, andpreferably from 3 to 6 hydroxyl groups in a molecule. Use of polyetherpolyols having less than two hydroxyl groups in a molecule (polyetherdiol) may result in insufficient photocurability of the resincomposition and decreased mechanical properties, in particular, lowmodulus of elasticity of the resulting three-dimensional objects. On theother hand, if polyether polyols having more than six hydroxyl groups ina molecule are used, the resulting three-dimensional objects may exhibitinsufficient elongation and decreased moisture resistance.

As examples of the polyol, polyether polyols obtained by modifyingpolyhydric alcohols having more than three hydroxyl groups such astrimethylolpropane, glycerol, pentaerythritol, sorbitol, sucrose, andquadrol with cyclic ether compounds such as ethylene oxide (EO),propylene oxide (PO), butylene oxide, and tetrahydrofuran can be given.Specific examples include EO-modified trimethylolpropane, PO-modifiedtrimethylolpropane, tetrahydrofuran-modified trimethylolpropane,EO-modified glycerol, PO-modified glycerol, tetrahydrofuran-modifiedglycerol, EO-modified pentaerythritol, PO-modified pentaerythritol,tetrahydrofuran-modified pentaerythritol, EO-modified sorbitol,PO-modified sorbitol, EO-modified sucrose, PO-modified sucrose,EO-modified sucrose, EO-modified quadrol and the like. Of these,EO-modified trimethylolpropane, PO-modified trimethylolpropane,PO-modified glycerol, PO-modified sorbitol are preferred.

The molecular weight of the polyether polyol is preferably 100-2,000,and more preferably 160-1,000. If the molecular weight of the polyetherpolyol is too small, form stability and physical stability ofthree-dimensional objects formed from the resin composition may beinsufficient. On the other hand, if the molecular weight of thepolyether polyol is too large, increased viscosity of the resincomposition may give rise to lower modulus of elasticity of thethree-dimensional objects formed by photofabrication.

As examples of commercially available products of polyether polyols,Sunnix TP-400, GP-600, GP-1000, SP-750, GP-250, GP400, GP-600(manufactured by Sanyo Chemical Industries, Ltd.), TMP-3 Glycol, PNT4Glycol, EDA-P-4, EDA-P-8 (manufactured by Nippon Nyukazai Co., Ltd.),G-300, G-400, G-700, T-400, EDP-450, SP-600, SC-800 (manufactured byAsahi Denka Kogyo Co., Ltd.), and the like can be given.

These polyether polyols can be used either individually or incombinations of two or more.

The proportion of the polyol used in the photocurable resin compositionof the present invention is usually, relative to the total composition,5-35 wt %, preferably 7-30 wt %, and more preferably 10-25 wt %.

Description of Calculation Method and Test Methods

Calculation of Boltzmann Averaged Dipole Moment

The Boltzmann averaged dipole moment is calculated in the following way.First, for the acrylate under consideration a set of startingconfigurations is generated by considering all possible bond rotations.This is done by means of the Discover 95 program (Computational resultsobtained using software programs from Molecular Simulations—force fieldcalculations were done with the Discover® program, using the CVFFforcefield, semi-empirical calculations were done the MOPAC 6.0program).

Torsional angles considered depend on the type of bond, e.g. for a bondbetween two sp³ carbons the angles taken into account are thosecorresponding to the two possible gauche conformations and the transconformation. The number of configurations generated is thus dependenton both the number of bonds and their type. E.g. for three sp³ likebonds one has 3⁵=243 configurations. As a consequence, for some of theacrylates, the total number of configurations was a few thousand.

All these configurations are then minimized at the AM1 level using MOPAC6.0 with the convergence criterion for the maximum gradient (GNORM) setto 0.05. The resulting structures are then sorted by energy and only theunique structures having a heat of formation differing less than 3kcal/mole from the heat of formation of the global minimum structure areretained. Whether or not structures are unique is determined bycomparing their heats of formation and their dipole moments in thefollowing way. First, structures are considered to be identical if theirheats of formation differ at most 0.01 kcal/mole. Neverheless,structures which are considered to be identical based on this energycriterion are considered to be unique if their dipole moments differmore than 0.2 Debye.

Having determined the unique structures, the Boltzmann weighted dipolemoment is consequently evaluated as given by formula (18):$\begin{matrix}{{< D>={\sum\limits_{j}\quad{D_{j}\frac{{\mathbb{e}}^{{- \Delta}\quad{H_{j}/{RT}}}}{\sum\limits_{i}\quad{\mathbb{e}}^{{- \Delta}\quad{H_{i}/{RT}}}}}}} = {\sum\limits_{j}\quad{D_{j}p_{j}}}} & (18)\end{matrix}$with D j the dipole moment of conformation j, ΔH j the differencebetween the heat of formation of conformation j and the heat offormation of the global minimum conformation, T the absolute temperatureand R the Boltzmann constant, p j is the probability of finding themolecule in conformation j at the temperature T. T is set to 298.15 K.The summation over j runs over all unique structures. Sorting ofstructures, retaining only the unique ones and the calculation of <D> isdone by means of a FORTRAN program developed in.

The advantage of considering the Boltzmann weighted dipole momentinstead of the dipole moment of the global minimum structure is that theformer takes into account the fact that several conformations can beaccessible at T. It is obvious that when the dipole moments of theaccessible conformations are significantly different, the value of <D>may be significantly different from the dipole moment of the globalminimum. The Boltzmann weighted dipole moment therefore provides a muchmore realistic description of the system.

RT FTIR Measurements

A 10 micron thick layer of the reactive composition on a gold coatedAlumina plate was cured in a RT-FTIR instrument under a nitrogenatmosphere (Bruker IFS 55 equiped with a transflection cell and a UVsource, an Oriel system with a 200 W Hg lamp, for a full description ofthe equipment see: A. A. Dias, H. Hartwig, J. F. G. A. Jansen conferenceproceedings PRA Radcure coating and inks; curing and performance June1998 paper 15). The consumption of acrylate bonds was measured at 21° C.during the curing by this technique and the maximum rates of acrylateconversions (in mol/l sec) were calculated according to the above citedreference.

Determination of Dielectric Constants

The determination of the dielectric constant was performed according toASTM D150 employing a Novocontrol Alpha analyzer, using a liquidmeasuring cel with a gap of 4.86 mm and a diameter of 20.7 mm. Themeasurements were performed at 23° C. The dielectric constants at 10 KHzare given.

Method for Calculating the Volumetric Thermal Expansion Coefficient

The thermal expansion coefficient α₂₃ for several coating systems can bepredicted on the basis of chemical structural information by usingcommercial software packages: the module Synthia of MSI (MolecularSimulations Inc, San Diego, Calif.) in combination with the Buildermodule of MSI. Synthia version 8.0 and the standard Builder modulewithin the Insight II (4.0.0 P) graphical environment were used. Thecomputations were performed on a Silicon Graphics O2 workstation under aUnix based operating system. The builder module is applied for theconstruction of the chemical monomer species that will serve as inputfor the Synthia module. This module Synthia is based on a methodologydeveloped by J. Bicerano that is explained in detail in his monograph(J. Bicerano, Prediction of polymer properties, Marcel Dekker Inc., NewYork, 1993). This methodology makes use of compositional information,i.e. the chemical monomer structure, for the prediction of polymerproperties. In particular, connectivity indices based on graph theoryare used. This methodology is developed for the prediction ofproperties, among these properties the thermal expansion coefficient, oflinear amorphous homopolymers and for linear alternating and randomamorphous copolymers. The term linear refers to non-crosslinked systems.The primary coatings according to the present invention may be treatedas linear copolymers because their thermal expansion coefficient dependson the cohesive energy density, and thus most significantly on thepolarity and not on the network characteristics of the coatings. Thepolarity is identical for a network system or it's linear analogue. So,this linear analogue, a linear statistical copolymer is constructedbased on the chemical recipe of the coatings. The software programcalculates the thermal expansion coefficient at 23° C. (α₂₃).

Experimental Section

EXAMPLES 1-6 AND COMPARATIVE EXPERIMENTS A-O

Boltzmann average dipole moments of functional groups which have beenattached to an acrylate group have been calculated. Examples 1-6 showfunctional groups, attached to an acrylate group, falling under theinvention. Comparative experiments A-O show acrylates which are known inthe art, which show a low Boltzmann average dipole moment and do notfall under the present invention.

Cure speeds of the monomers of examples 1-6 and comparative experimentshave been measured; 1% irgacure 184 (w/w) was dissolved in the monomerand the cure was monitored by RT-FTIR. The RT-FTIR measurement ofExample 5 is carried out at 50° C., because the monomer of Example 5 isa solid at room temperature. dipole AM1 rate Example Structure (Debye(mol/l sec) 1

3.87 17.9 2

4.12 17.9 3

4.54 17.55 4

6.5 33 5

7.38 38 (at 50° C.) 6

4.62 25.2

Comparative Experiments: Calculated Boltzman average Dipole moments (3.5Debye and lower) and rates of pure monomers are given. Comparativedipole AM1 rate Experiment Structure (Debye (mol/l sec) A

1.8 2.2 B

2.01 1.04 C

2.05 5.3 D

2.08 5.83 E

2.17 7 F

2.20 0.88 G

2.24 2.1 H

2.40 3.95 I

2.42 2.67 J

2.49 4.12 K

2.59 4.11 L

2.65 8.2 M

2.93 14 N

2.95 2.7 O

3.30 4.79

These results clearly indicate that generally available monomers withlow dipole moments do not show very high polymerization rates. Muchhigher rates of polymerization are obtained employing monomers withhigher dipole (examples 1-6).

Moreover comparison of example 3 with example 6 shows two monomers thathave a comparable high dipole moment. The rate of polymerization of themonomer of example 6 is even higher than the rate of polymerization ofthe monomer of example 3. This difference is due to the ability offormation of H-bonds of the monomer of example 6, which gives anadditional increase of the rate of polymerization.

EXAMPLE 7

1% Irgacure 184 was dissolved in a mixture of oxazolidone acrylate (amonomer with a high calculated dipole moment of D=5.3) andtetrahydrofurfuryl acrylate (a monomer with a low calculated dipolemoment of D=2.05). The ratio of the two monomers has been changed in theseries of experiments, thereby changing the calculated dipole moment ofthe mixture of the two monomers and the dielectric constant of thecomposition. The rates of polymerization were determined with the aid ofRT-FTIR. The results are shown in the next table. mixture (%)

Dipole (Debye) rate (mol/l sec) 100 0 2.05 5.3 90 10 2.35 5.79 80 202.66 7.46 70 30 2.97 9.75 60 40 3.28 12.52 30 70 4.27 17.23 20 80 4.6120.63 10 90 4.95 22.72 0 100 5.3 27.29

This example 7 clearly shows the surprising effect of an increase of therate of polymerization when using an increasing amount of monomershaving a high dipole moment.

EXAMPLE 8

Example 8 shows the effect of the use of a nonreactive diluent(propylene carbonate, having a high calculated dipole moment of D=5) onthe rate of polymerization;

1% Irgacure 184 was dissolved in a mixture of propylene carbonate (D=5)and tetrahydrofurfuryl acrylate (a monomer having a low calculateddipole moment of D=2.05). The rates were determined with RT-FTIR using atransmissision setup between two NaCl plates. Due to this change insetup the light intensity was reduced resulting in a lower maximum rateof polymerization for tetrahydrofurfuryl acrylate. The results are shownin the next table. Amount propylene carbonate (% w/w) Dipole (debye)Rate (mol/l sec) 0 2.05 3.17 10 2.48 3.62 20 2.86 4.26 30 3.21 4.77

This example shows that addition of a nonreactive compound having a highdipole moment also enhances the rate of polymerization.

EXAMPLES 9-18 AND COMPARATIVE EXPERIMENTS P-R

A number of urethane acrylates have been prepared, having functionalgroups having high calculated dipole moments.

The synthesis of these compounds has been performed as follows:

Under stirring 1 eq of an hydroxy functional acrylate was added to amixture of 1 eq of a diisocyanate containing 0.05% dibutyltin dilauratewhilst dry air was bubbled through the mixture at such a rate that thetemperature did not rise above 35° C.

After complete addition of the hydroxy functional acrylatel eq of ahydroxy group containing compound having a functional group having ahigh dipole moment was added at once after which the temperature wasraised to 80° C. and kept at that temperature for an additional 2 hours.

These samples were mixed with hydroxy ethyl acrylate (HEA) (50% w/w) and1% Irgacure 184 after which the RT-FTIR profile was recorded. Theresults are shown in the following tables: dipole moment of Rate alcohol(mol/l Example Acrylate Diisocyanate Alcohol (Debye) sec) 9 HEA IPDI

5.64 29 10 HEA IPDI

4.75 30 11 HEA IPDI

4.18 37 12 HEA IPDI

4.07 32 13 HEA IPDI

3.17 30 14 HEA IPDI

3.13 31 15 HPA IPDI

4.18 34 16 HBA IPDI

4.18 27 17 HEA TD1

4.18 35 18 HEA HDI

4.18 30

Comparative experiment Dipole moment Rate Comparative of alcohol (mol/lexperiment Acrylate diisocyanate Alcohol (Debye) sec) P HEA IPDI

1.65 19 Q HEA IPDI

1.69 20 R HEA IPDI

1.96 17Abbreviations:HEM hydroxy ethyl acrylate,HPA = 2-hydroxy propyl acrylate,HBA = 4-hydroxy butyl acrylate,IPDI = sophorone diisocyanate,TDI = toluene diisocyanate,HDI = hexane diisocyanate

These examples and the comparative experiments clearly show that(meth)acrylate functional urethanes from alcohols with dipolemoments >2.5 possess higher rates of polymerization compared tofunctional urethanes of alcohols with dipoles lower than 2.

EXAMPLES 19-22 AND COMPARATIVE EXPERIMENT S

A number of radiation curable optical fiber coating compositions hasbeen prepared containing a radiation curable oligomer (A) and at leastone reactive diluent (B). The coating compositions can be used asprimary coating compositions, and ultimately as secondary coatingcompositions.

The synthesis of the oligomer has been performed in accordance with thesynthesis of oligomer 1 of Example II of U.S. Pat. No. 5,219,896. Theoligomer is an aliphatic polyether-polycarbonate based urethaneacrylate.

The oligomer was mixed with other ingredients to form radiation curableoptical fiber coating compositions as indicated in the following table.The dielectric constants were measured and the RT-FTIR profiles wererecorded: % w/w Ex.19 Ex.20 Ex.21 Ex.22 Comp.Exp.S Oligomer 52 52 52 5252 SR504 32 32 32 32 32 IDA 11.5 Monomer of EX.11 (D of 11.5 alchohol =4.18) Monomer of Ex.3 (D = 4.54) 11.5 Monomer of Ex.4 (D = 6.5) 11.55-ring cyclic carbonate 11.5 ester acrylate Lucirin TPO 3 3 3 3 3Irganox 1035 0.5 0.5 0.5 0.5 0.5 Silane A189 0.25 0.25 0.25 0.25 0.25Silane Z6040 0.25 0.25 0.25 0.25 0.25 Tinuvin 292 0.5 0.5 0.5 0.5 0.5Dielectric constant at 10 7.22 8.13 8.64 9.15 6.12 kHz Rate (mol/l sec)3.53 3.88 4.17 4.40 2.67Abbreviations and Tradenames:SR504=ethoxylated (n=4) nonyl phenol acrylate, IDA=isodecyl acrylate,Lucerin TPO=2,4,6-trimethylbenzoyl diphenyl phosphine oxide (BASF),Irganox 1035=thiodiethylene bis-(3,5-di-tertiary-butyl-4-hydroxy)hydrocinnamate (antioxidant), A-189=1-propanethiol, 3-(trimethoxysilyl)adhesion promotor, Z6040=a silane adhesion promotor, Tinuvin292=UV-absorber, 5-ring cyclic carbonate esteracrylate=2-oxo-1,3-dioxolan-4-yl-methyl acrylate according to formula(19)

These examples and comparative experiments clearly show that the maximumrate of polymerization increases upon increasing the dielectric constantof the primary coating composition.

EXAMPLE 23 AND COMPARATIVE EXPERIMENT T Secondary Coating Composition

Oligomer T is an aromatic polyether based urethane acrylate oligomerhaving a Mw of 1000, which is derived from 2-hydroxyethylacrylate,toluene diisocyanate, and a polyether diol. Comparative Experiment TSecondary coating composition Components Wt % Oligomer T 34.17Ethoxylated (n = 3) bisphenol A 56 diacrylate Ethoxylated (n = 4) nonylphenol 6.09 acrylate Photoinitiators Lucerin TPO 1.07 Irgacure 184 2.14Irganox 1035 0.53 Properties Dielectric constant at 10 kHz at 6.94 23°C.

Example 23 is a secondary coating composition comparable to ComparativeExperiment T wherein the 6.09 wt % of ethoxylated (n=4) nonylphenolacrylate has been replaced by 6.09 wt % of the monomer of Example 4(having a dipole moment D=6.5 Debye). The dielectric constant at 10 kHzat 23° C. of the secondary coating of example 23 is 7.78.

EXAMPLE 24 AND COMPARATIVE EXPERIMENT U Matrix Composition

The matrix composition of Comparative Experiment U contains 40 wt. % ofan oligomer U which is an aromatic polyether based urethane acrylateoligomer, derived from 2-hydroxyethylacrylate, toluene diisocyanate, anda polytetramethylene glycol having Mn Of 1000, 30 wt. % ethoxylated(n=3) bisphenol A diacrylate, 8 wt % hexane diol diacrylate and 10 wt %isobornyl acrylate. The composition has a dielectric constant at 10 kHzat 23° C. of 8.68.

Example 24 is a matrix composition similar to Comparative Experiment U,but wherein isobornyl acrylate has been replaced by 10 wt. % of themonomer of Example 4 (having a dipole moment D=6.5 Debye). Thedielectric constant at 10 kHz at 23° C. of the matrix composition ofexample 24 is 9.37.

EXAMPLE 25 AND COMPARATIVE EXPERIMENT V Clear for Ink Composition

The clear composition of Comparative experiment V contains 21 wt. % ofan oligomer V which is Ebecryl 264 (an 85% aliphatic urethanetriacrylate oligomer/15% hexane diol diacrylate monomer blend,theoretical Mw of 2000), 32 wt. % of ethoxylated (n=3) bisphenol Adiacrylate, 16 wt. % of penta erythrithol tetra acrylate and 7 wt. % ofisobornyl acrylate. The composition has a dielectric constant at 10 kHzat 23° C. of 8.19.

Example 25 is a clear composition similar to Comparative Experiment V,but wherein isobornyl acrylate has been replaced by 7 wt. % of themonomer of Example 4 (having a dipole moment D=6.5 Debye). Thedielectric constant at 10 kHz at 23° C. of the clear composition ofexample 25 is 9.11.

EXAMPLE 26

A secondary coating composition was formulated using 50 wt. % of analiphatic polyether based urethane acrylate oligomer (the oligomer isderived from 2-hydroxyethylacrylate, isophorone diisocyanate, andpolytetrahydrofuran having Mn of 1000), 32.8 wt. % of2-hydroxyethylacrylate, 17.2 wt. % of HEA-IPDI-5CC adduct (as describedfor coating U in Table 1 above) and 1 wt. % of Irgacure 184.

The calculated α₂₃ is 6.42×10⁻⁴ K⁻¹, the rate of polymerization is 2.99mol/l sec.

EXAMPLE 27

A secondary coating composition was formulated using 50 wt. % of analiphatic polyether based urethane acrylate oligomer (the oligomer isderived from 2-hydroxyethylacrylate, isophorone diisocyanate, andpolytetrahydrofuran having Mn of 1000), 32.8 wt. % of2-hydroxyethylacrylate, 17.2 wt. % of ethoxylated (n=4) nonyl phenolacrylate and 1 wt. % of Irgacure 184.

The calculated ≦₂₃ is 6.71×10⁻⁴ K⁻¹. The rate of polymerization is 2.67mol/l sec.

1-34. (canceled)
 35. A process for preparing a radiation curablecomposition, comprising: reacting together (i) an hydroxy-, thiol- orNH-functional (meth)acrylate, (ii) a di-or more functional isocyanate,and (iii) an hydroxy-, thiol- or NH-functional compound having acalculated Boltzmann average dipole moment of greater than 2.5 Debyewherein one or more compounds formed are chosen from the groupconsisting of compounds (C1) according to the formula (1):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅,R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P; X is an oxygenor sulfur atom; Y is an oxygen or sulfur atom or an NR₇-group; n is 0-4;m is 0-4 and n+m=1-4; or compounds (C2) according to formula (2):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is0-4 and n+m=2-4, or compounds (C3) according to the formula (3):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; X and W are independently an oxygen or sulfuratom; Y is an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is 0-4and n+m=1-4; or a compound (C4) according to the formula (4):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂, and R₃, are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkyl group can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an aryl group havingfrom 6-20 C-atoms; X and W are independently an oxygen or sulfur atom; nis 1-4; or a compound (C5) according to the formula (5):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂, and R₃ are independently of each other H, an alkyl group having 1-20C atoms, wherein the alkyl group can be linear, branched or cyclic andmay contain heteroatoms like ═N, O, S and P or an aryl group having from6-20 C-atoms; X is an oxygen or sulfur atom; Y is an oxygen or sulfuratom or an NR₇-group; n is 1-5; p=0, 1; but excluding a compound whereinR₁═CH₂CHCO₂CH₂CH₂ or R1=CH₂CCH₃CO₂CH₂CH₂ with n=2, 3 and X=Y=oxygen, ora compound (C6) according to the formula (6):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is0-4 and n+m=1-4, or a compound (C7) according to the formula (7):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; W, X, Y and Z are independently an oxygen orsulfur atom or an NR₇-group with the proviso that W and X are not bothan NR₇-group at the same time; n is 1-4; or a compound (C8) according tothe formula (8):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃, and R₇ are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkyl group can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an aryl group havingfrom 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 1-4; or acompound (C9) according to the formula (9):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃, and R₇ are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkyl group can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an aryl group havingfrom 6-20 C-atoms; X is an oxygen or sulfur atom; Y is an oxygen orsulfur atom or an NR₇-group; n is 1-4.
 36. The process of claim 35wherein one or more of the compounds formed as defined in claim 1 isprepared by reacting together (i) an hydroxy functional (meth)acrylate,(ii) a di-functional isocyanate, and (iii) a hydroxy functional compoundhaving a calculated Boltzmann average dipole moment of greater than 2.5Debye.
 37. The process of claim 35 wherein one or more of the compoundsformed as defined by claim 35 is prepared by reacting together (i) oneequivalent of a hydroxy functional (meth)acrylate, (ii) two equivalentsof a di-functional isocyanate, (iii) one equivalent of a diamine,dihydroxy or dithiol functional compound with a molecular weight Mn of1000 or less, and (iv) one equivalent of a hydroxy functional compoundhaving a calculated Boltzmann average dipole moment of greater than 2.5Debye.
 38. The process of claim 35 wherein one or more of the compoundsformed as defined by claim 35 is prepared by reacting together (i) oneequivalent of a hydroxy functional (meth)acrylate, (ii) two equivalentsof a di-functional isocyanate, (ii) one equivalent of a diamine,dihydroxy or dithiol functional compound with a molecular weight Mn ofgreater than 1000, and (iii) one equivalent of a hydroxy functionalcompound having a calculated Boltzmann average dipole moment of greaterthan 2.5 Debye.
 39. The process of claim 35 wherein one or more of thecompounds formed as defined by claim 35 is prepared by reacting together(i) an hydroxy functional (meth)acrylate, (ii) a tri-or more functionalisocyanate, (iii) a hydroxy functional compound having a calculatedBoltzmann average dipole moment of greater than 2.5 Debye together, and(iv) a hydroxy or amine functional oligomer with an average hydroxy oramine functionality greater than 1.5.
 40. The process according to claim35, wherein the compound includes a functional group which when attachedto an acrylate group has a calculated Boltzmann average dipole moment ofgreater than 3.5 Debye.
 41. The process according to claim 40, whereinthe functional group when attached to an acrylate group has a calculatedBoltzmann average dipole moment of greater than 4.5 Debye.
 42. Theprocess of claim 35 further comprising coating a glass fiber with one ormore compounds as defined in claim 35 and curing the composition.
 43. Anoptical fiber coating composition comprising: one or more compoundschosen from the group consisting of compounds (C1) according to theformula (1):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅,R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P; X is an oxygenor sulfur atom; Y is an oxygen or sulfur atom or an NR₇-group; n is 0-4;m is 0-4 and n+m=1-4; or compounds (C2) according to formula (2):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is0-4 and n+m=2-4, or compounds (C3) according to the formula (3):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; X and W are independently an oxygen or sulfuratom; Y is an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is 0-4and n+m=1-4; or a compound (C4) according to the formula (4):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂, and R₃, are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkyl group can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an aryl group havingfrom 6-20 C-atoms; X and W are independently an oxygen or sulfur atom; nis 1-4; or a compound (C5) according to the formula (5):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂, and R₃ are independently of each other H, an alkyl group having 1-20C atoms, wherein the alkyl group can be linear, branched or cyclic andmay contain heteroatoms like ═N, O, S and P or an aryl group having from6-20 C-atoms; X is an oxygen or sulfur atom; Y is an oxygen or sulfuratom or an NR₇-group; n is 1-5; p=0, 1; but excluding a compound whereinR₁═CH₂CHCO₂CH₂CH₂ or R₁═CH₂CCH₃CO₂CH₂CH₂ with n=2, 3 and X=Y=oxygen, ora compound (C6) according to the formula (6):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is0-4 and n+m=1-4, or a compound (C7) according to the formula (7):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; W, X, Y and Z are independently an oxygen orsulfur atom or an NR₇-group with the proviso that W and X are not bothan NR₇-group at the same time; n is 1-4; or a compound (C8) according tothe formula (8):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃, and R₇ are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkyl group can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an aryl group havingfrom 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 1-4; or acompound (C9) according to the formula (9):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃, and R₇ are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkyl group can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an aryl group havingfrom 6-20 C-atoms; X is an oxygen or sulfur atom; Y is an oxygen orsulfur atom or an NR₇-group; n is 1-4.
 44. The optical fiber coatingcomposition of claim 43, further comprising N-vinylpyrrolidone.
 45. Theoptical fiber coating composition of claim 43, further comprisingN-vinylcaprolactam.
 46. A coated optical fiber comprising a glassoptical fiber, a primary coating applied thereon, a secondary coatingapplied on the primary coating and optionally an ink composition appliedon the secondary coating, wherein at least one of the primary coating,secondary coating or ink composition comprises one or more of thefollowing compounds: compounds (C1) according to the formula (1):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅,R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P; X is an oxygenor sulfur atom; Y is an oxygen or sulfur atom or an NR₇-group; n is 0-4;m is 0-4 and n+m=1-4; or compounds (C2) according to formula (2):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is0-4 and n+m=2-4, or compounds (C3) according to the formula (3):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; X and W are independently an oxygen or sulfuratom; Y is an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is 0-4and n+m=1-4; or a compound (C4) according to the formula (4):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂, and R₃, are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkyl group can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an aryl group havingfrom 6-20 C-atoms; X and W are independently an oxygen or sulfur atom; nis 1-4; or a compound (C5) according to the formula (5):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂, and R₃ are independently of each other H, an alkyl group having 1-20C atoms, wherein the alkyl group can be linear, branched or cyclic andmay contain heteroatoms like ═N, O, S and P or an aryl group having from6-20 C-atoms; X is an oxygen or sulfur atom; Y is an oxygen or sulfuratom or an NR₇-group; n is 1-5; p=0, 1; but excluding a compound whereinR₁═CH₂CHCO₂CH₂CH₂ or R1=CH₂CCH₃CO₂CH₂CH₂ with n=2, 3 and X=Y=oxygen, ora compound (C6) according to the formula (6):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is0-4 and n+m=1-4, or a compound (C7) according to the formula (7):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; W, X, Y and Z are independently an oxygen orsulfur atom or an NR₇-group with the proviso that W and X are not bothan NR₇-group at the same time; n is 1-4; or a compound (C8) according tothe formula (8):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃, and R₇ are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkyl group can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an aryl group havingfrom 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 1-4; or acompound (C9) according to the formula (9):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃, and R₇ are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkyl group can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an aryl group havingfrom 6-20 C-atoms; X is an oxygen or sulfur atom; Y is an oxygen orsulfur atom or an NR₇-group; n is 1-4.
 47. An optical fiber according toclaim 46, wherein at least one of the compounds has a calculatedBoltzman average dipole moment of higher than 2.5 Debye.
 48. Opticalfiber ribbon comprising a plurality of coated, and optionally coloredoptical fibers arranged in a plane and embedded in a matrix composition,wherein the coated optical fiber is a fiber according to claim
 46. 49.The process according to claim 35 further comprising coating a surfaceof one or more polycarbonate substrates with one or more compoundsaccording to claim
 35. 50. The process according to claim 49 wherein theone or more compounds on the one or more coated polycarbonate substratesare cured with ultraviolet radiation at a dose of 0.2-1.0 J/cm².
 51. Theprocess according to claim 49 wherein two coated polycarbonatesubstrates are superimposed on each other to form a single DVD.
 52. Anadhesive compound comprising: one or more of the following compounds:compounds (C1) according to the formula (1):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅,R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P; X is an oxygenor sulfur atom; Y is an oxygen or sulfur atom or an NR₇-group; n is 0-4;m is 0-4 and n+m=1-4; or compounds (C2) according to formula (2):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is0-4 and n+m=2-4, or compounds (C3) according to the formula (3):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; X and W are independently an oxygen or sulfuratom; Y is an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is 0-4and n+m=1-4; or a compound (C4) according to the formula (4):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂, and R₃, are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkyl group can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an aryl group havingfrom 6-20 C-atoms; X and W are independently an oxygen or sulfur atom; nis 1-4; or a compound (C5) according to the formula (5):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂, and R₃ are independently of each other H, an alkyl group having 1-20C atoms, wherein the alkyl group can be linear, branched or cyclic andmay contain heteroatoms like ═N, O, S and P or an aryl group having from6-20 C-atoms; X is an oxygen or sulfur atom; Y is an oxygen or sulfuratom or an NR₇-group; n is 1-5; p=0, 1; but excluding a compound whereinR₁═CH₂CHCO₂CH₂CH₂ or R1=CH₂CCH₃CO₂CH₂CH₂ with n=2, 3 and X=Y=oxygen, ora compound (C6) according to the formula (6):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 0-4; m is0-4 and n+m=1-4, or a compound (C7) according to the formula (7):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃,R₄,R₅, R₆ and R₇ are independently of each other H, an alkyl grouphaving 1-20 C atoms, wherein the alkyl group can be linear, branched orcyclic and may contain heteroatoms like ═N, O, S and P or an aryl grouphaving from 6-20 C-atoms; W, X, Y and Z are independently an oxygen orsulfur atom or an NR₇-group with the proviso that W and X are not bothan NR₇-group at the same time; n is 1-4; or a compound (C8) according tothe formula (8):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃, and R₇ are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkyl group can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an aryl group havingfrom 6-20 C-atoms; X is an oxygen or sulfur atom; Y and Z areindependently an oxygen or sulfur atom or an NR₇-group; n is 1-4; or acompound (C9) according to the formula (9):

wherein R₁=organic group with a molecular weight between 40 and 20000;R₂,R₃, and R₇ are independently of each other H, an alkyl group having1-20 C atoms, wherein the alkyl group can be linear, branched or cyclicand may contain heteroatoms like ═N, O, S and P or an aryl group havingfrom 6-20 C-atoms; X is an oxygen or sulfur atom; Y is an oxygen orsulfur atom or an NR₇-group; n is 1-4.
 53. A radiation curable DVDadhesive comprising the composition of claim
 52. 54. A DVD comprisingtwo polycarbonate substrates adhered to each other using a compositionof claim 52.